Earlier studies have indicated that Jun/AP-1 activity is associated with, and probably required f... more Earlier studies have indicated that Jun/AP-1 activity is associated with, and probably required for apoptosis induction by DNA-damaging and stress-inducing agents in human myeloid cells. To investigate this possibility, we examined the capacity of continuous treatments with etoposide (10 microM) and camptothecin (0.4 microM), and pulse treatments with X-rays (20 Gy), heat (2 h at 42.5 C) and cadmium chloride (2 h at 200 microM) followed by recovery, to provoke apoptosis and to simulate c-jun and c-fos expression and AP-1 binding in U-937 human promonocytic cells. All these treatments generated apoptosis with similar efficacy (50-60% apoptotic cells at 6 h of treatment or recovery). However, the capacity to increase c-jun and c-fos mRNA levels and to stimulate AP-1 binding was very different, ranging from more than a twelve-fold increase in the case of cadmium, to almost no increase in the case of heat-shock and etoposide. When the cells were pre-conditioned with a soft heat shock (1 h at 42 degrees C) the cadmium-provoked apoptosis was greatly inhibited, but the stimulation of AP-1 binding was not affected. The administration of cAMP-increasing agents also reduced the etoposide- and cadmium-provoked apoptosis. However, cAMP greatly stimulated c-jun and c-fos expression and AP-1 binding when applied together with etoposide (which itself was ineffective), and potentiated the cadmium-induced AP-1 binding. Conversely, retinoic acid abrogated the cadmium-provoked stimulation of AP-1 binding and transactivation capacity, and greatly inhibited the stimulation of binding caused by camptothecin and X-rays. However, retinoic acid did not inhibit the induction of apoptosis by these agents. These results indicate that Jun/AP-1 activity is not necessarily coupled with apoptosis, nor required for apoptosis induction by DNA-damaging and stress-inducing agents in human promonocytic cells.
Treatment of U-937 promonocytic cells with the DNA topoisomerase II inhibitor etoposide rapidly c... more Treatment of U-937 promonocytic cells with the DNA topoisomerase II inhibitor etoposide rapidly caused death by apoptosis, as determined by changes in chromatin structure, production of DNA breaks, nucleosome-sized DNA degradation, decrease in mitochondrial membrane potential and phosphatidyl serine translocation in the plasma membrane, and at the same time induced intracellular acidification. Both the execution of the apoptotic process and the intracellular acidification were reduced by the addition of forskolin plus theophylline or other cAMP increasing agents. These agents also attenuated the induction of apoptosis by camptothecin, heat-shock, cadmium chloride and X-radiation. Although etoposide slightly increased the production of reactive oxygen intermediates, this increase was not prevented by forskolin plus theophylline, and the addition of antioxidant agents failed to inhibit apoptosis. Etoposide caused a great increase in NF-(kappa)B binding activity, which was not prevente...
... Cytotoxicity of bare and PEGylated silica nanoparticles as potential gene-delivery vectors. C... more ... Cytotoxicity of bare and PEGylated silica nanoparticles as potential gene-delivery vectors. C. Yagüe, L. Saldaña, F. Martin, M. Arruebo, N. Vilaboa, J. Santamaria Universidad feZaragoza, ES. ... Nanotech 2008 Conference Program Abstract. ...
A literature review of electrochemical impedance spectroscopy (EIS) analysis of proton exchange m... more A literature review of electrochemical impedance spectroscopy (EIS) analysis of proton exchange membrane fuel cells (PEMFCs) is presented. Emphasis is placed on the papers that analyse the impedance response of the cathode and anode half-cells of the PEMFCs based on a continuum-mechanics approach. The other type of analysis, which is based on the equivalent-circuits approach, is addressed for comparison. The relative advantages and disadvantages of the two approaches are discussed. Papers dealing with continuum-mechanics-based EIS modelling of general electrochemical systems are briefly reviewed.
Advanced nanomechanical testing has been used to evaluate the mechanical properties of Ni-free Al... more Advanced nanomechanical testing has been used to evaluate the mechanical properties of Ni-free Al 12 (Fe,Cr) 3 Si 2 intermetallic coatings grown on 316 LVM steel by hot dipping in a Al-12.6 at.% Si liquid alloy for various immersion times. Despite the ultrafine-grained structure of the coating (~ 200 nm), the indentation size effect is more pronounced for the intermetallic coating than for the steel, which is explained by their higher geometrically necessary dislocation (GND) density. To determine the true hardness of the coatings, the model of Nix and Gao was used. It has been shown that the hardness of the coating decreases from 6.2 GPa for the shortest time of immersion (60 s), to 3.36 GPa for the highest immersion time (600 s), which is always much higher than that for the substrate (1.82 GPa). The decrease in both hardness and GND with increasing immersion time is related to the relaxation of residual stresses, which act as a hardening agent. The net effect is an increase of the plasticity index of the coating.
The administration of 150 nM etoposide, an inhibitor of DNA topoisomerase II activity, decreased ... more The administration of 150 nM etoposide, an inhibitor of DNA topoisomerase II activity, decreased the proliferation and induced the differentiation of U937 human promonocytic cells, as determined by nitroblue tetrazolium reduction, surface accumulation of CD11b/CD18 and CD11c/CD18 integrins, and c-fms protooncogene expression. The expression of these differentiation markers started to be detected at 24 h of treatment. Etoposide caused little cell damage, as determined by trypan blue exclusion and by apoptotic-like DNA degradation, which was slightly initiated at 48 h. The treatment induced a transient increase in c-fos, c-jun, and jun B mRNA levels, with maximum values at 12 h, a transient increase in collagenase mRNA level, with maximum value at 48 h, and a progressive increase in vimentin and lamin A and C mRNAs. These changes were qualitatively similar to those produced by 12-O-tetradecanoylphorbol-13-acetate. Etoposide also caused a transient increase of total AP-1 binding activity, with maximum value at 12 h of treatment, as determined by gel retardation assays. The drug produced an early transient activation (3-6 h) of membrane-bound protein kinase C, followed by the later activation (48 h) of both the membrane and cytosolic enzyme. The protein kinase C inhibitors, sphinganine and 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H7), attenuated the induction of differentiation markers by etoposide. These results suggest that protein kinase C and AP-1-dependent gene expression could be involved in myeloid cell differentiation by DNA topoisomerase II inhibitors.
Implantation of scaffolds may elicit a host foreign body response triggered by monocyte/macrophag... more Implantation of scaffolds may elicit a host foreign body response triggered by monocyte/macrophage lineage cells. Growing evidence suggests that topographical cues of scaffolds play an important role in MSC functionality. In this work, we examined whether surface topographical features can regulate paracrine interactions that MSCs establish with macrophages. Three-dimensional (3D) topography sensing drives MSCs into a spatial arrangement that stimulates the production of the anti-inflammatory proteins PGE 2 and TSG-6. Compared to two-dimensional (2D) settings, 3D arrangement of MSCs cocultured with macrophages leads to an important decrease in the secretion of soluble factors related with inflammation and chemotaxis including IL-6 and MCP-1. Attenuation of MCP-1 secretion in 3D cocultures correlates with a decrease in the accumulation of its mRNA levels in MSCs and macrophages. Using neutralizing antibodies, we identified that the interplay between PGE 2 , IL-6, TSG-6 and MCP-1 in the co-cultures is strongly influenced by the micro-architecture that supports MSCs. Local inflammatory milieu provided by 3D-arranged MSCs in co-cultures induces a decrease in monocyte migration as compared to monolayer cells. This effect is partially mediated by reduced levels of IL-6 and MCP-1, proteins that up-regulate each other's secretion. Our findings highlight the importance of topographical cues in the soluble factor-guided communication between MSCs and macrophages. Biomaterials j o u r n a l h o m e p a g e : w w w .e l se v i e r. co m/ lo ca t e / b i o m a t e ri a l s http://dx.
El acero inoxidable austenítico 316 LVM es un material que combina buenas propiedades mecánicas c... more El acero inoxidable austenítico 316 LVM es un material que combina buenas propiedades mecánicas con una razonable biocompatibilidad in vitro y tolerancia in vivo. Su bajo coste y fácil mecanización lo hace muy apreciado en la fabricación de una gran variedad de componentes para implantes. Estos componentes generalmente carecen de tratamiento superficial. Sin embargo, estudios recientes consideran que una mejora de la estabilización a corto plazo del implante puede ser crítico en las etapas iniciales. Los resultados in vivo han puesto de manifiesto que las superficies rugosas de los implantes de Ti producen una fijación mejor que la correspondiente a superficies lisas [ 1,2 ]. La mejor osteointegración, fijación y estabilidad de los implantes es una consecuencia del aumento del área disponible para la aposición del hueso al implante (fijación mecánica).
We investigated whether near-infrared (NIR) light could be employed for patterning transgene expr... more We investigated whether near-infrared (NIR) light could be employed for patterning transgene expression in plasmonic cell constructs. Hollow gold nanoparticles with a plasmon surface band absorption peaking at ∼750 nm, a wavelength within the so called "tissue optical window", were used as fillers in fibrin-based hydrogels. These composites, which efficiently transduce NIR photon energy into heat, were loaded with genetically-modified cells that harbor a heat-activated and ligand-dependent gene switch for regulating transgene expression. NIR laser irradiation in the presence of ligand triggered 3-dimensional patterns of transgene expression faithfully matching the illuminated areas of plasmonic cell constructs. This non-invasive technology was proven useful for remotely controlling in vivo the spatiotemporal bioavailability of transgenic vascular endothelial growth factor. The combination of spatial control by means of NIR irradiation along with safe and timed transgene induction presents a high application potential for engineering tissues in regenerative medicine scenarios.
Cancer therapy has been characterized throughout history by ups and downs, not only due to the in... more Cancer therapy has been characterized throughout history by ups and downs, not only due to the ineffectiveness of treatments and side effects, but also by hope and the reality of complete remission and cure in many cases. Within the therapeutic arsenal, alongside surgery in the case of solid tumors, are the antitumor drugs and radiation that have been the treatment of choice in some instances. In recent years, immunotherapy has become an important therapeutic alternative, and is now the first choice in many cases. Nanotechnology has recently arrived on the scene, offering nanostructures as new therapeutic alternatives for controlled drug delivery, for combining imaging and treatment, applying hyperthermia, and providing directed target therapy, among others. These therapies can be applied either alone or in combination with other components (antibodies,
Earlier studies have indicated that Jun/AP-1 activity is associated with, and probably required f... more Earlier studies have indicated that Jun/AP-1 activity is associated with, and probably required for apoptosis induction by DNA-damaging and stress-inducing agents in human myeloid cells. To investigate this possibility, we examined the capacity of continuous treatments with etoposide (10 microM) and camptothecin (0.4 microM), and pulse treatments with X-rays (20 Gy), heat (2 h at 42.5 C) and cadmium chloride (2 h at 200 microM) followed by recovery, to provoke apoptosis and to simulate c-jun and c-fos expression and AP-1 binding in U-937 human promonocytic cells. All these treatments generated apoptosis with similar efficacy (50-60% apoptotic cells at 6 h of treatment or recovery). However, the capacity to increase c-jun and c-fos mRNA levels and to stimulate AP-1 binding was very different, ranging from more than a twelve-fold increase in the case of cadmium, to almost no increase in the case of heat-shock and etoposide. When the cells were pre-conditioned with a soft heat shock (1 h at 42 degrees C) the cadmium-provoked apoptosis was greatly inhibited, but the stimulation of AP-1 binding was not affected. The administration of cAMP-increasing agents also reduced the etoposide- and cadmium-provoked apoptosis. However, cAMP greatly stimulated c-jun and c-fos expression and AP-1 binding when applied together with etoposide (which itself was ineffective), and potentiated the cadmium-induced AP-1 binding. Conversely, retinoic acid abrogated the cadmium-provoked stimulation of AP-1 binding and transactivation capacity, and greatly inhibited the stimulation of binding caused by camptothecin and X-rays. However, retinoic acid did not inhibit the induction of apoptosis by these agents. These results indicate that Jun/AP-1 activity is not necessarily coupled with apoptosis, nor required for apoptosis induction by DNA-damaging and stress-inducing agents in human promonocytic cells.
Treatment of U-937 promonocytic cells with the DNA topoisomerase II inhibitor etoposide rapidly c... more Treatment of U-937 promonocytic cells with the DNA topoisomerase II inhibitor etoposide rapidly caused death by apoptosis, as determined by changes in chromatin structure, production of DNA breaks, nucleosome-sized DNA degradation, decrease in mitochondrial membrane potential and phosphatidyl serine translocation in the plasma membrane, and at the same time induced intracellular acidification. Both the execution of the apoptotic process and the intracellular acidification were reduced by the addition of forskolin plus theophylline or other cAMP increasing agents. These agents also attenuated the induction of apoptosis by camptothecin, heat-shock, cadmium chloride and X-radiation. Although etoposide slightly increased the production of reactive oxygen intermediates, this increase was not prevented by forskolin plus theophylline, and the addition of antioxidant agents failed to inhibit apoptosis. Etoposide caused a great increase in NF-(kappa)B binding activity, which was not prevente...
... Cytotoxicity of bare and PEGylated silica nanoparticles as potential gene-delivery vectors. C... more ... Cytotoxicity of bare and PEGylated silica nanoparticles as potential gene-delivery vectors. C. Yagüe, L. Saldaña, F. Martin, M. Arruebo, N. Vilaboa, J. Santamaria Universidad feZaragoza, ES. ... Nanotech 2008 Conference Program Abstract. ...
A literature review of electrochemical impedance spectroscopy (EIS) analysis of proton exchange m... more A literature review of electrochemical impedance spectroscopy (EIS) analysis of proton exchange membrane fuel cells (PEMFCs) is presented. Emphasis is placed on the papers that analyse the impedance response of the cathode and anode half-cells of the PEMFCs based on a continuum-mechanics approach. The other type of analysis, which is based on the equivalent-circuits approach, is addressed for comparison. The relative advantages and disadvantages of the two approaches are discussed. Papers dealing with continuum-mechanics-based EIS modelling of general electrochemical systems are briefly reviewed.
Advanced nanomechanical testing has been used to evaluate the mechanical properties of Ni-free Al... more Advanced nanomechanical testing has been used to evaluate the mechanical properties of Ni-free Al 12 (Fe,Cr) 3 Si 2 intermetallic coatings grown on 316 LVM steel by hot dipping in a Al-12.6 at.% Si liquid alloy for various immersion times. Despite the ultrafine-grained structure of the coating (~ 200 nm), the indentation size effect is more pronounced for the intermetallic coating than for the steel, which is explained by their higher geometrically necessary dislocation (GND) density. To determine the true hardness of the coatings, the model of Nix and Gao was used. It has been shown that the hardness of the coating decreases from 6.2 GPa for the shortest time of immersion (60 s), to 3.36 GPa for the highest immersion time (600 s), which is always much higher than that for the substrate (1.82 GPa). The decrease in both hardness and GND with increasing immersion time is related to the relaxation of residual stresses, which act as a hardening agent. The net effect is an increase of the plasticity index of the coating.
The administration of 150 nM etoposide, an inhibitor of DNA topoisomerase II activity, decreased ... more The administration of 150 nM etoposide, an inhibitor of DNA topoisomerase II activity, decreased the proliferation and induced the differentiation of U937 human promonocytic cells, as determined by nitroblue tetrazolium reduction, surface accumulation of CD11b/CD18 and CD11c/CD18 integrins, and c-fms protooncogene expression. The expression of these differentiation markers started to be detected at 24 h of treatment. Etoposide caused little cell damage, as determined by trypan blue exclusion and by apoptotic-like DNA degradation, which was slightly initiated at 48 h. The treatment induced a transient increase in c-fos, c-jun, and jun B mRNA levels, with maximum values at 12 h, a transient increase in collagenase mRNA level, with maximum value at 48 h, and a progressive increase in vimentin and lamin A and C mRNAs. These changes were qualitatively similar to those produced by 12-O-tetradecanoylphorbol-13-acetate. Etoposide also caused a transient increase of total AP-1 binding activity, with maximum value at 12 h of treatment, as determined by gel retardation assays. The drug produced an early transient activation (3-6 h) of membrane-bound protein kinase C, followed by the later activation (48 h) of both the membrane and cytosolic enzyme. The protein kinase C inhibitors, sphinganine and 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H7), attenuated the induction of differentiation markers by etoposide. These results suggest that protein kinase C and AP-1-dependent gene expression could be involved in myeloid cell differentiation by DNA topoisomerase II inhibitors.
Implantation of scaffolds may elicit a host foreign body response triggered by monocyte/macrophag... more Implantation of scaffolds may elicit a host foreign body response triggered by monocyte/macrophage lineage cells. Growing evidence suggests that topographical cues of scaffolds play an important role in MSC functionality. In this work, we examined whether surface topographical features can regulate paracrine interactions that MSCs establish with macrophages. Three-dimensional (3D) topography sensing drives MSCs into a spatial arrangement that stimulates the production of the anti-inflammatory proteins PGE 2 and TSG-6. Compared to two-dimensional (2D) settings, 3D arrangement of MSCs cocultured with macrophages leads to an important decrease in the secretion of soluble factors related with inflammation and chemotaxis including IL-6 and MCP-1. Attenuation of MCP-1 secretion in 3D cocultures correlates with a decrease in the accumulation of its mRNA levels in MSCs and macrophages. Using neutralizing antibodies, we identified that the interplay between PGE 2 , IL-6, TSG-6 and MCP-1 in the co-cultures is strongly influenced by the micro-architecture that supports MSCs. Local inflammatory milieu provided by 3D-arranged MSCs in co-cultures induces a decrease in monocyte migration as compared to monolayer cells. This effect is partially mediated by reduced levels of IL-6 and MCP-1, proteins that up-regulate each other's secretion. Our findings highlight the importance of topographical cues in the soluble factor-guided communication between MSCs and macrophages. Biomaterials j o u r n a l h o m e p a g e : w w w .e l se v i e r. co m/ lo ca t e / b i o m a t e ri a l s http://dx.
El acero inoxidable austenítico 316 LVM es un material que combina buenas propiedades mecánicas c... more El acero inoxidable austenítico 316 LVM es un material que combina buenas propiedades mecánicas con una razonable biocompatibilidad in vitro y tolerancia in vivo. Su bajo coste y fácil mecanización lo hace muy apreciado en la fabricación de una gran variedad de componentes para implantes. Estos componentes generalmente carecen de tratamiento superficial. Sin embargo, estudios recientes consideran que una mejora de la estabilización a corto plazo del implante puede ser crítico en las etapas iniciales. Los resultados in vivo han puesto de manifiesto que las superficies rugosas de los implantes de Ti producen una fijación mejor que la correspondiente a superficies lisas [ 1,2 ]. La mejor osteointegración, fijación y estabilidad de los implantes es una consecuencia del aumento del área disponible para la aposición del hueso al implante (fijación mecánica).
We investigated whether near-infrared (NIR) light could be employed for patterning transgene expr... more We investigated whether near-infrared (NIR) light could be employed for patterning transgene expression in plasmonic cell constructs. Hollow gold nanoparticles with a plasmon surface band absorption peaking at ∼750 nm, a wavelength within the so called "tissue optical window", were used as fillers in fibrin-based hydrogels. These composites, which efficiently transduce NIR photon energy into heat, were loaded with genetically-modified cells that harbor a heat-activated and ligand-dependent gene switch for regulating transgene expression. NIR laser irradiation in the presence of ligand triggered 3-dimensional patterns of transgene expression faithfully matching the illuminated areas of plasmonic cell constructs. This non-invasive technology was proven useful for remotely controlling in vivo the spatiotemporal bioavailability of transgenic vascular endothelial growth factor. The combination of spatial control by means of NIR irradiation along with safe and timed transgene induction presents a high application potential for engineering tissues in regenerative medicine scenarios.
Cancer therapy has been characterized throughout history by ups and downs, not only due to the in... more Cancer therapy has been characterized throughout history by ups and downs, not only due to the ineffectiveness of treatments and side effects, but also by hope and the reality of complete remission and cure in many cases. Within the therapeutic arsenal, alongside surgery in the case of solid tumors, are the antitumor drugs and radiation that have been the treatment of choice in some instances. In recent years, immunotherapy has become an important therapeutic alternative, and is now the first choice in many cases. Nanotechnology has recently arrived on the scene, offering nanostructures as new therapeutic alternatives for controlled drug delivery, for combining imaging and treatment, applying hyperthermia, and providing directed target therapy, among others. These therapies can be applied either alone or in combination with other components (antibodies,
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Papers by Nuria Vilaboa